On Wednesday the Bank of England governor, Mark Carney, warned that commercial property prices would drop 48 per cent if a no-deal Brexit came about. He also predicted prices would drop, although not so drastically, in a deal scenario.

Portsmouth City Council's property portfolio includes a Matalan store in Swindon.

Portsmouth City Council has to date invested £146m of borrowed money into its property investment fund, made up of 13 commercial properties around the country, including a Waitrose in Somerset, a Matalan store in Swindon and a Mercedes dealership in Southampton.

If Mr Carney's predictions were realised this could mean a loss of more than £70m.

But for former council leader Cllr Donna Jones, who helped establish the fund, any concerns were unfounded. She said: 'Mark Carney made a number of predictions in 2016 about the effects of a Brexit outcome on the UK economy which were proved to be wrong.

'The council's property investment fund was set up with a view of owning these commercial properties and not selling them for a number of years.

'Therefore, if the value of the properties drop it is only significant at the point of when we would sell them. One of the key things is that the interest rates on the money we borrowed are fixed at two per cent.'

The council's head of planning, Cllr Ben Dowling, agreed. 'We would not sell the properties until the market picks up again,' he said.

'If it did crash we would wait for the market to recover before selling them. We would not sell an asset to a loss. And as a council we do have some financial protection. Our interest rates are set at two per cent.

'The other thing that protects the council's position is that we have quite a varied property investment portfolio. The mix de-risks what we are trying to do because if one loses value another one might support it.'

Chris Ward, the council's financial director, confirmed that a contingency plan was in place. He added: 'As a local authority with a number of commercial property investments it is essential that we have a robust plan in place to manage these investments.

'Our property and investment strategy details the council's objectives for acquiring property and the portfolio has been designed to guard against and minimise the council's exposure to all types of risk.'

So far the properties have generated an income of £8.4m a year and their market value has increased by 5.5 per cent, cancelling out the additional costs of buying the sites.